Refrigerant compressor



Dec. 22, 1942. I K|NG ETAL I 2,306,216

REFRIGERANT COMPRESSOR Filed Sept. 16, 1941 2 Sheets-Sheet- 1 Inventors:

Ralph E. King,

William L. Knaus,

b WW v The'm Attorney Dec. 22, 1 942. R 5 N ET AL 2,306,216

REFRIGERANT COMPRESSOR Filed Sept. 16, 1941 2 Sheets-Sheet 2 Fig. 3.

5 Inventsrs: Ralph E. King, William Knaus, y W

Th eh Attorney.

Patented Dec. 22, 1942 REFRIGERANT COMPRESSOR Ralph E. King and William L. Knaus, Fort Wayne, 11:11., assignors to General Electric Company, a corporation of New York Application September 16, 1941, Serial No. 411,035

3 Claims.

This invention relates to compressors and particularly to refrigerant compressors provided with devices for returning oil to the crankcase thereof.

During the operation of a compression type refrigerating machine a certain amount of oi or other lubricant is unavoidably entrained in the compressed refrigerant discharged to the condenser. It is, therefore, necessary to provide some arrangement for returning the lubricant to the compressor crankcase and many types of oil separating devices have been devised. Many of these devices are complicated and require additional working parts.

It is an object of this invention to provide a refrigerant compressor including a head provided with an improved arrangement for separating oil from the vaporized refrigerant returned to the compressor and for returning the oil to the crankcase.

It is another object of this invention to provide a refrigerant compressor having an improved oil separating arrangement of simple and rugged construction and which shall require no additional parts for the compressor.

Further objects and advantages of this invention will become apparent as the following description proceeds, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of this invention reference may be had to the accompanying drawings in which Fig. 1 is an elevational view partly in section of a refrigerant compressor embodying this invention; Fig. 2 is a diagrammatic illustration of the compressor shown in Fig. 1 connected in the refrigerant circuit of I. refrigerant machine; and Fig. 3 is an enlarged perspective exploded view of the head, valve plate, and'top of the block of the compressor shown in Fig. 1.

Briefly, the compressor shown in the drawings comprises a cylinder block in which is mounted a reciprocating piston and which is provided with a crankcase containing lubricating oil, a valve plate in which the intake and exhaust valves are mounted, and a head in which are secured the refrigerant suction and exhaust connections and in which are arranged pass-ages which cooperate with the valve plate to provide the intake and exhaust passages of the compressor. The intake passage is formed so that it includes a reverse turn whereby the refrigerant entering the compressor is forced to turn downwardly and back upon itself in order to reach the intake port. An oil return passage communicating with the crankcase is arranged at the bend in the intake passage so that the oil is thrown toward the oil return duct and enters the duct to be returned to the crankcase.

Referring now to the drawings, in Fig. l a compressor has been shown comprising a cylinder block In and a crankcase H formed integrally thereof and provided with supporting feet l2. A cylinder i3 is formed in the block l0 and a reciprocating piston I4 is mounted in the cylinder. The piston is reciprocated through a connecting rod l5 by operation of an electric motor (not shown) through a shaft 16 and a crank pin I1. The piston and rod [5 together with the crank are counterbalanced by a weight I8 to which isattached an oil scoop l9 arranged to dip into the oil indicated at 20 in the bottom of the crankcase to throw the oil upwardly so that it may be utilized to lubricate the working parts of the compressor. The counterweight i8 and scoop [9 are displaced, axially from the rod l5 so that they clear a boss or extension 2| of the block l0 within which the lower portion of the cylinder I3 is formed. The compressor is provided with a head 22 and a valve plate 23, suitable gaskets 24 and 25 being provided between the valve plate and the block and head respectively. The valve plate and head are securely held to the block by a plurality of bolts or cap screws 26. The head 22 is provided with an intake connection 21 to which a flange 28 of the suction line 29 is secured by suitable bolts 30. The head 22 is also pro- .vided. with an exhaust or discharge connection 3| to which a flange 32 of a discharge line 33 is secured by a plurality of bolts 34. A suitable fine mesh wire screen or filter 35 is arranged in the intake connection to prevent the passage of foreign matter to the compressor cylinder. The valve plate is provided with an intake port 38 controlled by an intake valve 31 of the reed type and an exhaust port 38 controlled by a suitable exhaust valve 39.

In Fig. 2 the compressor is shown connected in the circuit of a refrigerating machine including an evaporator 40 connected to the suction connection 28 by the suction line 29 and arranged to receive liquid refrigerant from a liquid receiver 4| through a liquid line 42 under control of a thermostatic expansion valve 43 having its thermal element 44 secured in heat exchange with the suction line. The discharge connection is arranged to conduct hot compressed refrigerant to the discharge line 33 through the connection 32 and thence to a condenser 45 where the refrigerant is cooled by air circulatedby a fan 48 driven by an electric motor 41. The refrigerant cooled and liquefied in the-condenser 45 flows through a connection, 48 to the liquid receiver 4|. During the operation of the refrigerating machine some of the lubricant is unavoidably entrained in the hot compressed refrigerant delivered to the condenser 45 and is carried with the liquid refrigerant though the liquid receiver and expansion valve to the evaporator. The inbricant may be returned to the compressor with the vaporized refrigerant flowing through the suction line. However, provision must also be made to separate the lubricant from the refrigerant and return the lubricant to the crankcase.

As shown in Fig. 1, an oil return duct 49 is provided in the block ill and the valve plate 23. Gaseous refrigerant and oil returning to the suction line 29 pass first through a substantially horizontal portion 50 of the inlet passage. This portion is formed entirely within the block 22 and terminates in an upright chamber 5| directly under the duct 49 so that any oil entrained in the gaseous refrigerant is thrown downwardly toward the duct and tends to flow into the duct. In order to reach the intake port 36, the refrigerant must pass through a reverse turn within the chamber 5| and back through a passage 52 formed by a recess in the bottom of the head 22 facing the top of the valve plate 23. A restricted opening 53 connects the passage 52 and the chamber 5| and facilitates the separation of oil from the gaseous refrigerant in the chamber 5| by increasing the turbulence adjacent the inlet of the oil return duct 49.

The arrangement of the passages in the head 22 and the manner in which the head and valve plate cooperate to provide the intake and exhaust passages is clearly shown in Fig. 3 in which the head and the valve plate and the block have been shown in an exploded view with the gaskets omitted. The exhaust valve 39 comprises a backing member 54 and a reed type valve 55 both secured to the plate 23 by suitable cap screws 56. The exhaust valve 39 is located in an exhaust chamber 51 which is separated from the intake chamber by an irregularly shaped wall 58. The intake valve 31 is securely held in place and the valve plate is also positioned on the block l by suitable pins 59. The opening movement of the intake valve is limited by a shoulder 60 formed by a recess in the block ID on the side of the cylinder l3 diametrically opposite the pins 59. The oil return duct 49 is located directly below the chamber which is formed in part by the wall 58. From Fig. 3 it is clear that the suction gas must pass through a reverse turn of substantially 180 in order to flow from th intake connection 21 to the intake port 36. The arrangement of the chamber 5| so that the oil return duct 49 is directly below the bend of the intake passage where the gas and oil mixture is flowing downwardly provides a simple and effective arrangement for assuring the return of the major portion of the oil to the crankcase. It has been found that in a compressor constructed in accordance with this invention, at least 70% of the oil entering the suction line is returned to the crankcase.

From the foregoing it is readily apparent that a simple and rugged arrangement has been provided whereby separation of oil from the suction gas is obtained without the necessity of additional parts either moving or stationary, the entire oil separating structure being formed within the compressor head.

While this invention has been described in connection with a particular form of compressor, other applications will be apparent to those skilled in the art. 'I'hisinvention is, therefore, not

limited to the particular construction shown and described, and it is intended in the appended claims to cover all modifications within the spirit and scope of this invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A refrigerant compressor comprising a cylinder block and a crankcase and a head for the cylinder block. said block having a cylinder therein. means providing intake and exhaust ports for said cylinder, said cylinder head having intake and exhaust passages formed therein and communicating respectively with saidiniake and exhaust ports, said intake passage having one portion extending across said head and having another portion extending backwardly substantially along said one portion to communicate with said intake port, said other portion of said passage lying below said one portion and said intake passage including a bend connecting said portions and being arranged to direct fluid downwardly toward said crankcase, and said block having a passage extending upwardly from said crankcase and communicating with said intake passage at the bend therein for receiving oil separated from the refrigerant in said intake passage at the bend therein and for conducting the oil to said crankcase.

2. A refrigerant compressor comprising 9. cylinder block and a crankcase and a head for the cylinder block, said block having a cylinder therein, a valve plate arranged between said head and said cylinder block and having intake and exhaust ports for said cylinder, said block and said valve plate having an oil return duct formed therein and communicating with said crankcase, and said intake passage comprising a portion extending across said head and formed entirely therein and a portion formed between said plate and said head and a downwardly extending chamber connecting said portions adjacent the upper ,end of said oil return duct so that fiuid passing through said intake passage must pass through a reverse bend adjacent said oil return duct in order to reach said intake port whereby oil is separated from the fluid and enters said oil retumduct.

3. A refrigerant compressor comprising a cylinder block and a crankcase and a head for the cylinder block, said block having a cylinder therein, a valve plate arranged between said head and said cylinder block and having intake and exhaust ports for said cylinder, said block and said valve plate having an 011 return duct formed therein and communicating with said crankcase, and said intake passage comprising a portion extending across said head and formed entirely therein and a portion formed between said plate and said head and a downwardly extending chamber connecting said portions adjacent the upper end of said oil return duct so that fluid passing through said intake passage must pass througha reverse bend adjacent said oil return duct in order to reach said intake port whereby oil is separated I from the fluid and enters said oil return duct. said portion of said intake passage between said chamber and said intake port being restricted adjacent said oil return duct to facilitate the return of oil to said crankcase.

RALPH E. KING. WILLIAM L. KNAUS. 

